Circuit breaker with pre-loaded terminal connectors

ABSTRACT

An electrical control device characterized by a drawout circuit breaker and spaced electrical stabs. The circuit breaker includes quick-detachable terminal connectors comprising a pair of oppositely disposed flexible stab contacts engageable with opposite sides of a stab and a spacer between the stab contacts for holding the stab contacts in spaced pre-loaded positions by a distance less than the thickness of the stab, whereby engagement of the stab contacts with the stab provides tight electrical contact therebetween.

, United States Patent [191 Maier et a1.

[451 Mar. 4, 1975 CIRCUIT BREAKER WITH PRE-LOADED TERMINAL CONNECTORS[75] Inventors: Alfred E. Maier, Beaver Falls;

James O. Rexroad, Beaver, both of [73] Assignee: Westinghouse ElectricCorporation,

Pittsburgh, Pa.

' [22] Filed: May 29,1973 t [21] App]. No.: 364,453

[52] US. Cl 339/147, 339/64, 200/50 AA,v

, 339/258 R [51] Int. Cl r; H0lr 3/00 [58] Field of Search 339/19, 147,258, 222,

339/64; 206/257, 258, 288, 50 AA, 48 KB [56] References Cited' UNlTEDSTATES PATENTS 3,015,083 12/1961 Juris 339/258 P X 3,274,532 Engel339/258 P 9/1966 3,343,042 9/1967 Cellerini et a1. ZOO/50 AA 3,744,0017/1973 Schor 339/14 R Primary Examiner-Roy D. Frazier AssistantE.\'aminerRobert A. Hafer Attorney, Agent, or Firm-L. P. Johns [57]ABSTRACT An electrical control device characterized by a drawout circuitbreaker and spaced electrical stabs. The circuit breaker includesquick-detachable terminal connectors comprising a pair of oppositelydisposed flexible stab contacts engageable with opposite sides of a staband a spacer between the stab contacts for holding the stab contacts inspaced pre-loaded positions by a distance less than the thickness of thestab, whereby engagement of the stab contacts with the stab providestight electrical contact therebetween.

6 Claims, 3 Drawing Figures CIRCUIT BREAKER WITH. PRE-LOADED TERMINALCONNECTORS BACKGROUND OF THE INVENTION 1. Fiel'dofthe Invention: I

This inventionrelates to detachable terminal connectorsfor acircuitbreaker and more particularly to flexible contacts for engagementwith corresponding stabs.

2. Description of the Prior Art:

Generally, circuit breakers of the drawout type are provided with springcontact fingers'that require only a small amount of movement to obtainfull engagement with electrical stabs that are aligned with the fingers.Where a large number of spring contact fingers and stabs for engagementtherewith are involved, a considerable amount of work is required forcomplete engagement. Accordingly,.there is a need for a more suitablemeans for obtaining a good electrical contact between the spring contactfingers and the stabs without reducing the force of engagement betweenthe fingers and the stabs when they are fully engaged.

SUMMARY OF THE INVENTION In accordance with this invention it has beenfound that the foregoing problem may be overcome by providing a circuitbreaker having quick-detachable terminal connectors, each connectorcomprising a pair of oppositely disposed flexible conductors engageableducing the force of contact between the fingers and the stabs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional viewbreaker of the drawout type;

- FIG. 2 is a, plan view of pre-loaded spring fingers or terminalconductors taken on the line IIII of FIG, 1 and FIG. 3 is a plan view ofone set of spring-fingers in through a circuit contact with a stab.

DESCRIPTION'OF THE PREFERRED I EMBODIMENT In FIG. 1 a circuit breaker isgenerally indicated at 11 and is generally similar in construction andoperation to that disclosed in US. Pat. No. 3,343,042 for which reasonan abbreviated description is set forth herein.

Briefly, the circuit breaker 11 comprises a housing 13 and a three-polecircuit breaker mechanism 19 supported within the housing. The housing13 includes a base 15 and a cover 17 both of which are composed ofmolded insulating material.

' The circuit breaker mechanism 19 comprises an operating mechanism 21which includes a pair of toggle links 23 and 25, a switch arm 27, acontact 28, a movable contact 29, a stationary contact 31., and a handle33. As shown in FIG. 1 the handle 33 is in the OFF position with thecontact 29 and 31 separated in the open each pole unit of the circuitbreaker extends from the terminal connector 39, the terminal 37, theconductor 35, the contacts 31 and 29, the contact arm 28, a flexibleconductor 45, a conductor 47, a terminal 49, and a terminal connector51.

As shown more particularly in FIG. 2 each terminal 37 comprises aplurality of horizontal members extending from the conductor 35.Moreover, the terminal connectors 39 and 51 of which the terminalconnectors 39 are shown in FIG.'2, comprise a pair of clip-on type orquick-detachable contacts which are connected by suitable means, such asnut and bolt assemblies 53, to and between the outer end portions of themembers of the terminals 37. Each terminal connector 39 comprises twoouter contacts or fingers 55 and two inner contacts or fingers 57, whichcontacts or fingers are elongated electrical conducting members composedof a flexible material such as sheet metal. As shown in FIG. 1 eachterminal connector 39 is split to provide eight separate pairs ofcontacts or fingers. In FIG. 2 each outer pair of contacts 55 is bentover at the outer end thereof to provide a generally rounded end portionforming a contact surface 59. Likewise, the inner pairs of contacts 57are provided with rounded end portions forming contact surfaces 61.

In accordance with this invention the terminal connectors 39 comprisethe contacts 55, 57 as well as the spacer 63 between each pair ofoppositely disposed contacts 55 and 57. Each pair of contacts 55 and 57are flared outwardly from their base positions on both sides of thespacer 63. In'the position shown in FIG. 2, the contacts 55 and'57 aremaintained in stressed positions so that both sides press againstopposite sides of the spacer 63. In fact, there may be enough stress onthe flexible contacts 55 and 57 to cause them to come together if thespacer 63 were eliminated. Suffice it to say, in'the positions shown inFIG. 2 the contacts 55 and 57 are spaced from each other by distancesslightly less'than the thickness of stabs and 67 which extend throughand are mounted in a support wall 69. Accordingly, when the circuitbreaker 11 moves to the right, as'viewed in'FlG. 2, the opposite pairsof contact surfaces 59 and 61 are in tight surface-to-surface electricalcontact with the stabs 65 and 67-and, inasmuch as the stabs are thickerthan the spacing between said surfaces before insertion of the stabs,the contacts 55 and 57 are moved away from opposite sides of the spacer63. It is noted that the prestressing of the contacts 55 and 57 by thespacer 63 does not diminish the final force of the contacts on thesurfaces of the stabs 65 and 67.

Another aspect of this invention is the provision of a spacer mountingportion or neck 71 between the base portion 6312 the spacer head portion63a. The neck 71 is flexible in order to yield in response to pressurefrom either side of the spacer. Such pressure occurs when the spacingbetween the center lines of a pair of stabs 65 and 67 is greater or lessthan the center lines between an adjacent pair of spacers 63. As shownin FIG. 3 a center line 73 for the terminal connector 39 which extendsthrough the spacer 63 is out of alignment with -a center line 75 of thestab 65 for some reason, such as improper spacing between the stabs 65and 67 or between phases. Accordingly, when the terminal connector 39moves intoengagement with the connector the upper side of the stab 65moves into engagement with the contact surfaces 59 and 61 and therebyraises the contacts 55 and 57 away from the upper side of the spacer63a. In response to the elimination of pressure from that side of thespacer,*the contacts 55 and 57 small amount of lateral movement of thefingers is nee-- essary when the drawout circuit breaker is moved intoengagement-with the stabsfThe contact force between the fingers and thestabs remain the same as though no spacer were provided and reduces thework required to move the circuit breaker into place. Finally, byproviding a spacer with a flexible neck or mounting portion the entireassembly of the fingers on opposite sides of the stab may move intocomplete electrical contact with any stab which is out of properalignment.

What is claimed is:

l. A circuit breaker for use 'in drawout switchgear having spaced linestabs and including a circuit breaker and a stationary housing havingstationary terminals, the stationary terminals being movableinto and outof contact with the line stabs, the circuit breaker comprising a pair ofseparable contacts, means for moving the contacts between open andclosed positions, first conductor means for connecting one of thecontacts to one of the stationary terminals, second conductor means forconnecting the other contact to the other terminal, each stationaryterminal comprising a quick detachable terminal connector, eachconnector including a pair of oppositely disposed flexible terminalcontacts engageable with opposite sides of a line stab, said oppositelydisposed terminal contacts being spaced. from each other by a distanceless than the thickness of a line stab when out of contact with saidstab, and a spacer between each pair of said terminal contacts, saidspacer being flexibly mounted to yield in response to pressure fromeither side of the spacer.

2. The circuit breaker of claim 1, in which the terminal connectors areelongated members having corresponding end portions fixedly mounted andhaving other end portions adapted to receive a terminal.

3. The circuit breaker of claim 2, in'which the terminal contactscomprise at least two'members disposed on opposite sides of the spacerand retained by the 1 spacer in spaced tension.

4. The circuit-breaker of claim 3, in which the terminal contactscomprise a pair of flexible members on opposite sides of the spacer, thepair of members on each side comprising a longer outer terminal contactand a shorter inner terminal contact.

5. The circuit breaker of claim 4, in which the end other side. isremoved.

1. A circuit breaker for use in drawout switchgear having spaced linestabs and including a circuit breaker and a stationary housing havingstationary terminals, the stationary terminals being movable into andout of contact with the line stabs, the circuit breaker comprising apair of separable contacts, means for moving the contacts between openand closed positions, first conductor means for connecting one of thecontacts to one of the stationary terminals, second conductor means forconnecting the other contact to the other terminal, each stationaryterminal comprising a quick detachable terminal connector, eachconnector including a pair of oppositely disposed flexible terminalcontacts engageable with opposite sides of a line stab, said oppositelydisposed terminal contacts being spaced from each other by a distanceless than the thickness of a line stab when out of contact with saidstab, and a spacer between each pair of said terminal contacts, saidspace being flexibly mounted to yield in response to pressure fromeither side of the spacer.
 2. The circuit breaker of claim 1, in whichthe terminal connectors are elongated members having corresponding endportions fixedly mounted and having other end portions adapted toreceive a terminal.
 3. The circuit breaker of claim 2, in which theterminal contacts comprise at least two members disposed on oppositesides of the spacer and retained by the spacer in spaced tension.
 4. Thecircuit breaker of claim 3, in which the terminal contacts comprise apair of flexible members on opposite sides of the spacer, the pair ofmembers on each side comprising a longer outer terminal contact and ashorter inner terminal contact.
 5. The circuit breaker of claim 4, inwhich the end portions of the terminal contacts are turned inwardly andoutwardly for surface contact with the terminals.
 6. The circuit breakerof claim 2, in which the spacer is an elongated element having one endportion seated between the fixedly mounted end portions of the elongatedmembers, the element having another end portion between the pair ofoppositely disposed flexible portions of the terminal contacts, and theelement having a flexible intermediate portion which is deflectable inresponse to pressure from the terminal contacts on one side whenpressure of the terminal contacts on the other side is removed.